Single-shot simulations of dynamics of quantum dark solitons

TL;DR

This paper investigates the emergence and dynamics of quantum dark solitons in one-dimensional Bose gases, analyzing how measurements and interactions influence their behavior and how many-body effects manifest over time.

Contribution

It provides a single-shot simulation framework for quantum dark solitons, exploring their formation, measurement-induced symmetry breaking, and evolution across different interaction regimes.

Findings

Mean-field predictions hold short-term in weak interactions.

Long-term dynamics show many-body effects and increased soliton position uncertainty.

Phase flips characteristic of solitons are observable even in strong interactions.

Abstract

Eigenstates of Bose particles with repulsive contact interactions in one-dimensional space with periodic boundary conditions can be found with the help of the Bethe ansatz. The type~II excitation spectrum identified by E. H. Lieb, reproduces the dispersion relation of dark solitons in the mean-field approach. The corresponding eigenstates possess translational symmetry which can be broken in measurements of positions of particles. We analyze emergence of single and double solitons in the course of the measurements and investigate dynamics of the system. In the weak interaction limit, the system follows the mean-field prediction for a short period of time. Long time evolution reveals many-body effects that are related to an increasing uncertainty of soliton positions. In the strong interaction regime particles behave like impenetrable bosons. Then, the probability densities in the configuration space become identical to the probabilities of non-interacting fermions but the wave-functions themselves remember the original Bose statistics. Especially, the phase flips that are key signatures of the solitons in the weak interaction limit, can be observed in the time evolution of the strongly interacting bosons.